The default engineers code is 1234 and the default user code is 4321 or the other way round on some units. The power should be from a fused spur point somewhere near the control box (not the keypad if remote), but remember the internal bettery will still power it without the mains.
I've got an installation manual in PDF format for the Texecom Veritas 8 that gives the instructions on what you want to do. I got it after being held to ransom by the local alarm company who'd changed it but wouldn't tell me the number for security reasons (found that was due to them using same number for all the alarms they "serviced" - some security!).
If you'd like the installation manual emailed to you then just text your email address to me at 07801 933766.
Stephen
March 2009